Radiometric methodology will be used to examine the biosynthesis and the principal metabolic pathways of estrogen and androgens in patients with breast, endometrial, and prostate cancer and compare these with suitable controls. The impact of endocrine therapy on these transformations will be measured to see whether it correlates with the response to the treatment. Dietary alterations in control patients will be carried out to observe their effect on the direction of estradiol metabolism, in the expectation that such may disclose a relationship between diet and risk for cancer. The receptor population of human breast, endometrial, and prostate tumor tissues will be measured with particular emphasis on the heterogeneity of the estradiol receptors. The receptor spectrum will be correlated with the clinical history of the patient. Studies will be continued into the basic mechanisms of estradiol biosynthesis and the role of its metabolism in target tissues in the expression of its various biological activities. The biosynthesis and function of the novel cortoic acids will remain an active area of investigation.